This invention relates to a process for roughening a surface of a ceramic and a process for producing a printed wiring board using the resulting surface roughened ceramic.
As surface roughening methods of ceramics, there have been known a process for treating a surface of ceramic with HF, HBF.sub.4, or the like for roughening and a process for treating a surface of ceramic with a molten alkali such as NaOH, KOH or the like.
On the other hand, a ceramic wiring board is produced by roughening a surface of a ceramic, subjecting to electroless plating, and if necessary electrical plating, to deposit a metal coating directly on the ceramic, and subjecting to etching or the like to form a conductor wiring. In this process, when the former surface roughening process is employed, adhesive strength between the metal coating and the ceramic becomes weak and there arises a defect in that the metal coating is to have blisters. On the other hand, when the latter surface roughening process is employed, good adhesive strength between the metal coating and the ceramic is not always obtained (i.e. sometimes the good adhesive strength is obtained, but sometimes no good adhesive strength is obtained, and the deviation is large), and blisters are generated in the metal coating when the thickness of electroless copper plated film is over 1 .mu.m, which results in making practical use impossible.